Evaluating Bioconcentration and Translocation Dynamics of Cadmium and Copper in Aquatic Macrophytes: Implications for Phytostabilization and Phytoextraction.

Abstract

Heavy metal contamination of soils and aquatic ecosystems poses ecological and health risks, with cadmium (Cd) and copper (Cu) among the most critical pollutants. Conventional remediation is often costly and disruptive, whereas phytoremediation offers a sustainable alternative. Yet, species-specific strategies in metal uptake remain insufficiently understood. This study examined the phytoremediation potential of four aquatic macrophytes viz. Alternanthera philoxeroides, Juncellus alopecuroides, Physalis minima, and Portulaca oleracea in pot experiments with graded Cd and Cu concentrations (50-400 mg kg⁻¹). Plants were cultivated for 60 days, harvested, and analysed for tissue accumulation using atomic absorption spectrophotometry. Uptake efficiency was assessed through bioconcentration factor (BCF), translocation factor (TF), and regression analyses.

Results showed a consistent tissue distribution of root > shoot > leaf for both metals, confirming root dominance in sequestration. A. philoxeroides and J. alopecuroides recorded root BCF > 3 with TF < 1, validating their role as Cd phytostabilizers. In contrast, J. alopecuroides displayed strong Cu phytoextraction, with shoot BCF > 2, steep regression slopes, and moderately higher TF values. A. philoxeroides showed moderate Cu accumulation, while P. minima and P. oleracea consistently exhibited low uptake, restricting their role to weak stabilization. Two-way ANOVA confirmed significant effects of species and concentration (p < 0.05), while regression models (R² > 0.95) demonstrated predictable dose–response relationships.

The study highlights distinct species-specific strategies: Cd phytostabilization and Cu phytoextraction. J. alopecuroides is identified as a strong Cu extractor and A. philoxeroides as a Cd stabilizer, offering practical applications for sustainable remediation.